THE RURAL WORLD.

King Country Chronicle, Volume VI, Issue 479, 3 July 1912, Page 7

THE RURAL WORLD.

NITRATE OF SODA AND' SULPHATE OF AMMONIA. For spine years a number of experiments have been conducted, at various experimental stations in Germany to test the relative fertilise ing efficacy of nitrate of soda and sulphate of ammonia. The results are discussed in an article in the Journal of the German' National Agricultural Society. At Darmstadt, as the result of 34 series of tests, comprising 1800 separate experiments, it was proyed that, putting the efficacy of nitrate of soda at 10U, the corresponding value of ammonia as, nitrogen was 94, or that it was necessary to apply 106 units of nitrogen in the form of ammonia to get equal resultß to 100 units nitrogen in nitrate of spda. This was the result arrived at scientifically, but in field practice the difference between the relative efficacy of the two fertilisers was found to be still greater and the average effect in ordinary farming seemed to be that while 60 parts out of every 100 parts nitrogen in nitrate of soda was taken up by the crop, v not more than 45 parts of the nitrogen as ammonia in sulphatee of ammonia was so utilised. In order to obtain an extra yield of five bushels of wheat, it may be considered necessary to apply | cwt. nitrate of soda, and according to the results obtained in the various trials the same quantity of sulphate of ammonia would have .to be employed. Why does the ammonia in sulphate of ammonia exercise on the crops a less relative effect? The chief reason would seem to be that part of the ammonia in the course of its'-- conversion in the soil into nitrogen is lust by evaporation. It would appear also that when sulphate of ammonia is applied to heavy clay soils, a small portion of the ammonia enters into combination in the soil of such a character that it becomes not available as plant food for some time. This point requires further elucidation, and experiments are being made to throw light upon it. How should nitrate of soda and sulphate of ammonia be applied so as to obtain the best |esults?' On this subject the results obtained have led to the following recommendations Oats: Sulphate of» ammonia should be applied in.one dose at time of sowing. Nitrate oif soda should also be broadcasted at time of / sowing, if only 1 cwt. per acre is applied; if a larger quantity,.than half at tinw of sowing, and half about four weeks later. '

Barley: When the application of sulphate of ammoniaor nitrate of soda is small, as it generally should be for this crop, say about 1 cwt. per: acre, it should be applied at the time of sowing. If, for any reason, larger quantities are applied, half at time of sowing and half about four weeks later. ''. '

Wheat: Autumn sown wheat should not receive applications of artificial nitrogen unless the land is very poor, and then onjy about 1 cwt to the acre. In spring the dressing should be, as a rule, about i cwt. nitrate of soda to the acre in one application. Larger quantities should be applied in two dressings.

Potatoes: The nitrogen should be applied in one dose at time !of planting, or, if the soil is very light, in two dressings, the first at. time of sowing, .and the second when the plants are hoed for the first time. Roots should receive the nitrogen at the time of sowing, except when the soil is very, light, when it should be applied in two dressings; half at time of planting and half at first hoeing. ( Thfl operation of top-dressing with nitrogen aslts should take place in dry weather, when rain may be expected, and mid-day after the dew has dried off, so that the salt does not stick to the leaves. Both nitrate of Boda and sulphate of ammonia give better results if they are ground fine before application, and mixed with sand or dry earth, so that the distribution may be more even. If Bulphate of ammonia is applied to land rich- in ime, or which has been recently , imed, it should be quickly ploughed or harrowed in, otherwise los 3of nitrogen will arise through the formation of volatile carbonate of ammonia. \l.

What effect have nitrogen salts oil the quality of .the drop product? On. this point there is a mass of statistics and reports, and the following conclusion may be drawn: —Applications of nitrogen increase to a small extent the percentage of nitrogenous substance in. grain-, roots, and potatoes. A similar, though still smaller effort has been noted in the straw and leaves of the crops. But other such as soil, weather, climate, variety, have far more influence in this respect than small applications of nitrogen. How much nitrogen does the soil yield to the crops. On an the surface soil to a depth of ten inched, is calculated to contain about 29001bs per acre,. and the crops—root crops included—are; calculated to extract 461bs per acre per year. , Thus it may be estimated that out of every 100 parts nitrogen in the soil 1.57 parts are extracted per year and per acre by the crops on an average.—Mark Lane Express.; -